The present invention relates to a constant flow and controlled ventilation, pressure responsive pulmotor. More particularly, the present invention relates to a pressure responsive pulmotor of the type mentioned above wherein means are provided for a control action intended for keying and detecting the behavior of the ventilation operation and possibly for modifying the same in real time according to the current needs. Pressure responsive pulmotors employed at present make use of mechanical devices, such as for instance of aneroid pressure gages for controlling and reading pressure values, so supplying only incomplete and approximate information about what is occurring within the circuit in which the patient is inserted.
In addition, the drawback of the manual recording of information data which requires quite long working times and implies the possibility of information loss adds to such uncontrolled running of the leaving parameters for carrying out correctly the ventilation operation.
It is clearly evident that there is the need for a constant flow pressure responsive pulmotor in which the intervention of the processing means causes visually observable information to be presented to the operator so as to allow an immediate control to be performed of mechanical ventilation, adapting the same to the clinical requirements and eliminating thus the drawbacks mentioned above which are due to the manual control of mechanical, pressure responsive ventilation machines known up to the present time.
In practice, and this normally occurs in the control system of the present invention, one or more parameters are keyed which can be defined as the keyed parameters and are characteristic of the operation and which are of such values as to exert on the operation itself the desired controlling action. More specifically, they are:
inhalation time Ti PA1 exspiration time Te PA1 peak pressure PIP PA1 final inhalation pressure PEEP PA1 pressure increase rate (flow in 1/minute). PA1 the inhalation rate (Rate) PA1 the inhalation/expiration ratio I/E PA1 the waveform (triangular wave, square wave) PA1 the pressure gradient between PIP and PEEP PA1 the mean inhalation pressure MIP PA1 the mean pressure over a whole respiratory cycle MAP which parameters allow the operator to estimate clinically the behavior of the therapeutical treatment as each one of them has a well definite clinical meaning. PA1 it avoids the alveolar collapse PA1 it exerts a protective action on the surfactant PA1 it decreases the resistance of the breathing apparatus PA1 the breathing rate (Rate) PA1 the inhalation time Ti PA1 the expiration time Te PA1 the ratio I/E PA1 the level of P.sub.MAX (PIP) PA1 the mean inhalation pressure value and the mean pressure in the whole respiratory cycle MIP-MAP PA1 the pressure level at the end of the expiration PEEP PA1 the ventilation time stored and in its lower portion, with a space for the visual presentation, on a pressure-time plot, of the pressure waveform as a function of the time between the successive inhalation (PIP) and expiration (PEEP) phases, said pressure waves pointing out in real time the value of the mean pressure in the respiratory apparatus during a whole respiratory cycle (MAP) as well as the mean value of pressures during the inhalation cycle only (MIP). PA1 1) the pressure increase rate PA1 2) PIP PA1 3) Ti PA1 4) PEEP PA1 5) Te.
Such keyed parameters correspond to those which are to be subjected to the desired behavior, and specifically: